In the formation of glassware it has been common practice to form a blank, or parison, in a parison mold portion of the glassware molding machine, to automatically transfer the parison to a blow mold portion of the glassware molding machine, and then to blow mold the parison into conformity to a blow mold.
In the parison mold portion of the glassware molding machine, a gob of molten glass is deposited into the parison mold; and a parison plunger is pressed into the parison mold, forcing the gob of glass into a parison that has the combined shape of the parison mold and the parison plunger.
The parison mold portion of the glassware molding machine includes a neck ring that is constructed of two neck ring halves, and that forms the finish portion, or threaded neck, of the parison.
It is this finish portion, or threaded neck, of the parison that is used in the blow mold portion of the glassware molding machine to hold the parison as the parison is blow molded to the final configuration of the glassware; and this same finish portion becomes the threaded neck of the completed container.
Since the finish portion, or threaded neck, of the parison is used to hold the parison for blow molding, the finish portion must be cool enough to have the physical properties that will enable it to withstand the blow molding process and still retain dimensional integrity for the completed container; and yet, the temperature of the parison must be sufficiently high to provide a viscosity that will blow mold.
Thus, it has been a problem to provide cooling for the neck ring that will provide mechanical strength and dimensional integrity in the finish portion of the parison while maintaining the remainder of the parison at a temperature that is sufficiently high to allow blow molding.
For a number of years the prior art has dealt with sundry means for cooling various components that mold glassware. The current state of art may best be shown, for example, in U.S. Pat. No. 3,024,571 by Abbott et al., in which internal cooling means is provided for glass molding surfaces. Although the patent discloses that cooling air currents may be used by allowing their passage through various components including ring arms, it has been found in actual practice that such methods fall short in providing an effective cooling process. Also related to the suject invention is U.S. Pat. No. 3,015,911 Payne, the patent disclosing a particular cooling scheme for forming neck finishes on glass containers. However, this patent deals with the blow mold side and does not deal with the blank or parison side of the glass forming operation.
In order to overcome the deficiencies in the processes, structural features for cooling glass molding surfaces and the products produced by glassware forming molds presently used, as well as those used heretofore, it is a principal object of the subject invention to provide improved details and characteristics on the blank mold side of a glass forming machine for sufficiently cooling in a controlled fashion a newly formed glass container, particularly the portion surrounding the mouth or opening of said container.
A further object of this invention is to provide means for adequately controlling the amount of heat that may be transferred between molding surfaces for glassware and uniformly cooling the surfaces of the glassware to render them free of any thermal checks or cracks thereon.
Another object of the subject invention is to optimize cooling effects during the formation of the blank or parison so that a finish of a newly produced glass container is formed having a flat terminal portion with a true circular mouth whereby a closure may be properly seated to seat the container.
Another object of the subject invention is to provide means for uniform and sufficient cooling of glassware, especially the finish thereof, without sacrifice of productivity and output from the individual sections of the glass-forming machines.
The subject invention provides means for increasing productivity of glassware and machine efficiency in excess of 10% or more without sacrifice of glassware quality.
Another important feature of the subject invention is that it provides means for controlled cooling on the blank side of a glassware forming machine so that certain treatments are minimized, including swabbing.